1. Field of the Invention
The present invention is directed to an X-ray system for the registration of X-ray datasets of a patient as well as to a method for determining the spatial relationship of X-ray datasets at a patient that are measured independently of one another.
2. Description of the Prior Art
Among other things, mobile C-arm x-ray apparatus with which regions of the patient can be radiologically acquired are utilized for medical or surgical interventions at a patient. As a result of this data acquisition, three-dimensional x-ray exposures can be acquired and presented on a picture screen. The reconstructed volume that can be presented with such three-dimensional x-ray data sets currently amounts to approximately (12 cm)3.
In many instances, however, a number of regions of the patient must be acquired that are spatially separated from one another. Since the x-ray data sets acquired in this way must be placed into a spatial relationship with each another for specific surgical interventions, an exact knowledge of the spacial positions of the individual x-ray data sets is required.
An example of this is a surgical intervention at the knee of a patient in the case of total knee replacement. Here, three-dimensional x-ray exposures (x-ray data sets) of the knee, the ankle and the hip are required, and their spatial relationship relative to one another must be known in order to be able to acquire the correct attitudinal and angular position of the knee joint.
German OS 199 17 867 discloses a method and an apparatus for positional allocation of a treatment devices to an x-ray exposure. The determination of the position data of the treatment region ensues with a camera-assisted navigation system and with the assistance of a reference structure simultaneously acquired with an x-ray exposure of the treatment region. A number of x-ray exposures of different regions of the treatment region can be compiled to form an overall image. A referencing device attached directly to the patient allows the patient to move between two x-ray exposures since this referencing device can be tracked by the navigation system.
An object of the present invention is to provide an x-ray system and a method employable with an x-ray system that, in a simple way and with little apparatus outlay, enable the exact determination of the spatial relationship between at least two x-ray data sets that were registered at different body segments of a patient.
This object is inventively achieved in an x-ray system and method according to a first embodiment of the invention wherein a scale is attached in the region wherein the x-ray data sets are registered and is visible in the registered x-ray data sets. The scale is rigidly attached in relationship to the patient and is visible in all registered x-ray data sets.
The scale, for example, can be attached to the patient directly or can be integrated in the operating table on which the patient lies during the intervention. In any case, the scale must be attached such that it is fixed in relationship to the patient.
This object also is achieved in a second embodiment of the invention, wherein the acquired spatial relationship of the registered x-ray data sets relative to one another is calculated and/or processed automatically by a processing device.
The automatic processing of the spatial acquired relationship by the processing device has the advantage that these relationships not only can be presented as information for the surgeon, but also can serve as a basis for further calculations. In this way, thus, an enlargement of the volume of the registered three-dimensional x-ray data sets can be achieved. To that end, a number of three-dimensional x-ray data sets are registered that spatially adjoin one another or spatially overlap one another slightly, and these are joined by the processing device and displayed on the picture screen.